Area under the curve that combines the individual severity of diarrhea toxicity as measured by the CTCAE v4.0 during and after RT [ Time Frame: Up to 6 weeks post radiation therapy ] [ Designated as safety issue: Yes ]

Average score for each outcome variable [ Time Frame: Up to 6 weeks post radiation therapy ] [ Designated as safety issue: No ]

Percentage of patients in each arm that experience each outcome variable during and after RT [ Time Frame: Up to 6 weeks post radiation therapy ] [ Designated as safety issue: No ]

Percent of patients in each arm that recorded "yes" to each of questions 2-12 on the bowel function questionnaire [ Time Frame: Up to 24 months post radiotherapy ] [ Designated as safety issue: No ]

Percentage of patients in each arm that require any and each type of antidiarrheal medications [ Time Frame: Up to 24 months post radiotherapy ] [ Designated as safety issue: No ]

Percentage of patients in each arm that experience clinically significant deficits in overall quality of life and fatigue [ Time Frame: Up to 24 months post radiotherapy ] [ Designated as safety issue: No ]

To determine whether sulfasalazine causes any toxicity in this situation.

Tertiary

To bank blood products for future studies, as part of ongoing research for NCCTG studies (Mayo Clinic Rochester only). (Translational)

OUTLINE: This is a multicenter study. Patients are stratified according to history of anterior resection of the rectum (yes vs no); total planned cumulative dosing, including boost fields of external-beam radiotherapy (4500-5350 cGy vs > 5350 cGy); and concurrent radiosensitizing fluorouracil, capecitabine, or oxaliplatin (yes vs no). Patients are randomized to 1 of 2 treatment arms.

NOTE: *Patients must start study treatment by the third radiotherapy fraction.

Patients may undergo blood sample collection at baseline and then weekly during radiotherapy. All patients complete quality of life and bowel function questionnaires at baseline, weekly during radiotherapy, and at 6 weeks after completion of radiotherapy.

After completion of radiotherapy, patients are followed up at 6 weeks and at 12 and 24 months.

Eligibility

Ages Eligible for Study:

18 Years and older

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

DISEASE CHARACTERISTICS:

Diagnosis of cancer that supports the use of radiotherapy to the pelvis

No current or prior metastases beyond pelvic regional lymph nodes

Planning to receive a course of continuous definitive or adjuvant external-beam radiotherapy to a minimum dose of 4500 cGy with or without fluorouracil, capecitabine, or oxaliplatin

Planned course of pelvic radiotherapy must fall within the following parameters:

Pelvis must be encompassed by the planned radiotherapy fields

Superior border may not lie superior to the L4-5 interspace and may not be inferior to the most inferior aspect of the sacroiliac joints

Portions of the rectum may have special blocking, depending upon disease site

Total planned dose to the central axis midplane (for AP-PA parallel opposed fields) or isocenter (for 3- or 4-field techniques) for the pelvic field must lie between 4500-5300 cGy (inclusive)*

Subsequent to completion of treatment to the pelvic field, a boost to primary tumor or tumor bed may be planned

Planned treatment is to be given 4-5 times per week on a one-treatment-per-day basis

Daily dose (specified at central axis midplane or at isocenter for multi-field techniques) must lie between 170-210 cGy (inclusive) per day*

NOTE: *For institutions that do not use midplane or isocenter as the point for specification of dose, it will be necessary to determine the dose according to the methods specified above in order to determine patient eligibility.

No perineal irradiation planned (e.g., anal cancer patients, patients who have had an abdominal-perineal resection)

No brachytherapy planned before the completion of all external-beam radiotherapy

No medical condition that may interfere with the ability to receive study treatment

No known allergy to sulfasalazine, sulfa medications, salicylates, or any known component of drug formulation

PRIOR CONCURRENT THERAPY:

See Disease Characteristics

No prior pelvic radiotherapy

No prior abdominal-perineal resection, Hartmann procedure, or other surgical procedure leaving the patient without a functioning rectum

No planned use of leucovorin or cytotoxic chemotherapeutic agents concurrent with radiotherapy (except for fluorouracil, capecitabine, or oxaliplatin)

No other concurrent sulfasalazine

No concurrent digoxin

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01198145